ASE L1 Domain 4: Fuel Systems and Air Induction Systems Diagnosis Welcome to your ASE L1 Domain 4: Fuel Systems and Air Induction Systems Diagnosis 1. ASE L1: Fuel Systems and Air Induction Systems Diagnosis A vehicle with a port fuel injection system exhibits lean running conditions and misfires. The long-term fuel trim is +25% at all engine speeds. The MOST likely cause is: A. Faulty oxygen sensors. B. Insufficient fuel pressure. C. Excessive exhaust backpressure. D. An intake manifold gasket leak. None 2. ASE L1: Fuel Systems and Air Induction Systems Diagnosis When a technician is testing a diesel engine's air induction system, they find oil contamination in the intercooler. What is the MOST likely source? A. A leaking turbocharger seal. B. Oil overfill condition. C. Faulty EGR cooler. D. A breach in the intercooler. None 3. ASE L1: Fuel Systems and Air Induction Systems Diagnosis A vehicle with sequential fuel injection has higher than normal short-term and long-term fuel trim readings on one bank only. A technician should FIRST check: A. The MAF sensor for contamination. B. The affected bank's fuel injectors for proper operation. C. For vacuum leaks affecting the entire engine. D. The integrity of the oxygen sensor's wiring and response. None 4. ASE L1: Fuel Systems and Air Induction Systems Diagnosis A GDI (Gasoline Direct Injection) engine is experiencing a rough idle and misfire codes. The technician should inspect the: A. Throttle body for carbon build-up. B. Injectors for coking and proper spray pattern. C. Fuel line for kinks or obstructions. D. All of the above. None 5. ASE L1: Fuel Systems and Air Induction Systems Diagnosis A technician receives a code P0171 (System Too Lean, Bank 1) on a V6 engine. After confirming the code, the technician should FIRST: A. Replace the bank 1 oxygen sensor. B. Check for a dirty MAF sensor. C. Perform a smoke test for intake leaks. D. Inspect the fuel pressure and volume. None 6. ASE L1: Fuel Systems and Air Induction Systems Diagnosis A vehicle equipped with a variable length intake manifold has a code set for the manifold tuning valve. Technician A says the valve may be stuck due to carbon build-up. Technician B says a vacuum leak at the intake manifold could cause this code. Who is correct? A. Technician A only. B. Technician B only. C. Both Technician A and B. D. Neither Technician A nor B. None 7. ASE L1: Fuel Systems and Air Induction Systems Diagnosis In a vehicle equipped with an after-market cold air intake system, a technician observes the code P0102 (Mass or Volume Air Flow Circuit Low Input). This could be due to: A. An oversized air filter allowing too much airflow. B. The MAF sensor positioned too close to the air filter. C. A high impedance in the MAF sensor circuit. D. All of the above. None 8. ASE L1: Fuel Systems and Air Induction Systems Diagnosis During a fuel pressure test on a multi-port fuel injected engine, the pressure drops rapidly after the pump is deactivated. This indicates: A. A failing fuel pressure regulator. B. One or more leaking fuel injectors. C. A defective fuel pump check valve. D. All of the above could be potential causes. None 9. ASE L1: Fuel Systems and Air Induction Systems Diagnosis When diagnosing an engine with a rough idle and no trouble codes, a technician finds that the fuel trims are normal at idle but become increasingly negative as RPM increases. This is indicative of: A. An air leak at higher engine speeds. B. Faulty fuel injectors providing too much fuel. C. Restricted air intake system. D. A malfunctioning throttle position sensor. None 10. ASE L1: Fuel Systems and Air Induction Systems Diagnosis A technician notes that an engine with a carburetor runs fine at idle but stumbles during acceleration. The MOST likely cause is: A. A faulty spark plug wire. B. A clogged air filter. C. An issue with the carburetor's accelerator pump. D. Incorrect ignition timing. None 1 out of 10 Time is Up! Time's up
